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Questions and Answers
What is the main purpose of a system catalog in a database?
What is the main purpose of a system catalog in a database?
Which language allows users to specify data structures and constraints in a database?
Which language allows users to specify data structures and constraints in a database?
What role does Data Manipulation Language (DML) play in a Database Management System?
What role does Data Manipulation Language (DML) play in a Database Management System?
Which of the following is NOT a function of a Database Management System (DBMS)?
Which of the following is NOT a function of a Database Management System (DBMS)?
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What is one of the key benefits of using views in a database?
What is one of the key benefits of using views in a database?
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What does a user-accessible catalog in a database primarily enable?
What does a user-accessible catalog in a database primarily enable?
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Which language is specifically designed for administering databases?
Which language is specifically designed for administering databases?
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Which of the following is not considered a component of the DBMS environment?
Which of the following is not considered a component of the DBMS environment?
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What role corresponds to the management of the database and ensuring data security?
What role corresponds to the management of the database and ensuring data security?
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Which system focuses on managing concurrent access to data in a database?
Which system focuses on managing concurrent access to data in a database?
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What is the primary function of Access Control Language (ACL) in a DBMS?
What is the primary function of Access Control Language (ACL) in a DBMS?
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Which generation of database systems introduced the relational model?
Which generation of database systems introduced the relational model?
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Which of the following is a disadvantage of using a DBMS?
Which of the following is a disadvantage of using a DBMS?
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What does the term 'data independence' refer to in a DBMS?
What does the term 'data independence' refer to in a DBMS?
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Which advantage is provided by a DBMS related to data accessibility?
Which advantage is provided by a DBMS related to data accessibility?
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What is a common procedure in the database management system environment?
What is a common procedure in the database management system environment?
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What is one of the main problems associated with file-based systems?
What is one of the main problems associated with file-based systems?
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What does a Database Management System (DBMS) primarily control?
What does a Database Management System (DBMS) primarily control?
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Which of the following is NOT a common application of database systems?
Which of the following is NOT a common application of database systems?
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What leads to data duplication in file-based systems?
What leads to data duplication in file-based systems?
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What is a key advantage of the database approach over the file-based approach?
What is a key advantage of the database approach over the file-based approach?
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Which of the following terms best describes a database?
Which of the following terms best describes a database?
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Which issue arises from data dependence in file-based systems?
Which issue arises from data dependence in file-based systems?
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What major limitation of file-based systems is caused by incompatible file formats?
What major limitation of file-based systems is caused by incompatible file formats?
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Study Notes
Introduction to Databases
- Databases are a shared collection of logically related data designed to meet organizational information needs.
- A system catalog (metadata) describes data, enabling program-data independence.
- Logically related data includes entities, attributes, and relationships of organizational information.
Chapter 1 Objectives
- Common database system uses are covered.
- Characteristics of file-based systems are explored.
- Problems with the file-based approach are examined.
- The meaning of "database" is defined.
- The meaning of "Database Management System (DBMS)" is defined.
- The typical functions of a DBMS are explained.
- Major DBMS environment components are detailed.
- Personnel in a DBMS environment are discussed.
- DBMS development history is reviewed.
- Advantages and disadvantages of DBMSs are analyzed.
Examples of Database Applications
- Purchases from supermarkets.
- Credit card purchases.
- Holiday bookings with travel agents.
- Library usage.
- Insurance applications.
- Video rentals.
- Internet access.
- University studies.
File-Based Systems
- A collection of application programs for end-users (e.g., reports).
- Each program defines and manages its own data.
Limitations of File-Based Approach
- Separation and Isolation of Data: Each program manages its own data, leading to potential unawareness of related data held by other programs.
- Data Duplication: Same data appears in multiple programs, wasting space and potentially leading to inconsistencies.
- Data Dependence: File structure is defined within the program code.
- Incompatible File Formats: Programs written in different languages cannot easily access each other's files.
- Fixed Queries/Proliferation of Application Programs: Programs are written for specific tasks, so new requirements often necessitate new programs.
Database Approach
- Data definition was embedded in application programs rather than being stored independently.
- No control over data access and manipulation beyond application programs.
- Result: The database and Database Management System (DBMS).
Database Management System (DBMS)
- A software system that allows defining, creating, maintaining, and controlling access to a database.
- The DBMS interacts with other programs (application programs) by receiving appropriate requests (SQL statements).
Database Approach (Continued)
- Data Definition Language (DDL): Defines data types, structures, and constraints.
- Data Manipulation Language (DML): Provides general inquiry facilities (query language) for data manipulation.
- Metadata is stored in the database.
Database Systems (Continued)
- Database Management System (DBMS) is software that defines, creates, maintains, and controls data access.
- DBMS uses Data Definition Language (DDL), Data Manipulation Language (DML).
- Query Language (QL) – retrieves data from a database.
- Access Control Language (ACL) - determines access levels.
- Database Administration Language (DAL) – administrates databases (logical or physical level).
Database Approach (Final Points)
- Controlled access to a database may include security, integrity, concurrency, recovery, and user-accessible catalogs.
Views
- Allows users to have their own views of the database.
- Essentially a subset of the database.
Views - Benefits
- Reduce complexity.
- Improve security.
- Customize database appearance.
- Present a consistent, unchanging view of the database even if the underlying database structure changes.
Components of DBMS Environment
- Hardware: From PCs to computer networks.
- Software: DBMS, operating system, network software, and application programs.
- Data: Used by the organization, with a description (schema).
- Procedures: Instructions and rules for database design and use.
- People: Involved in DBMS use (e.g., system analysts, database designers, application developers, DBAs, security administrators, naive and sophisticated end-users).
History of Database Systems
- First-generation: Hierarchical and Network databases.
- Second-generation (CSIT115): Relational databases.
- Third-generation (CSCI235): Object-Relational, Object-Oriented databases.
- Now: Cloud-based databases (e.g., covered in CSC1235).
Advantages of DBMSs
- Controls data redundancy.
- Enforces data consistency.
- Provides more info from the same data.
- Shares data.
- Improves data integrity.
- Improves security.
- Enforces standards.
- Provides economies of scale.
- Balances conflicting requirements, improving data accessibility & responsiveness & productivity.
- Improves maintenance through data independence, concurrency, and backup and recovery services.
Disadvantages of DBMSs
- Complex.
- Large Size.
- High cost of DBMS.
- More hardware costs.
- Costly conversion.
- Impacts of failure are greater.
- Performance Issues.
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Description
This quiz covers the essential concepts of databases, including their definition and the functions of Database Management Systems (DBMS). It explores the characteristics of file-based systems and the advantages and disadvantages of using a DBMS. Test your understanding of database applications and the components that make up a DBMS environment.
